Ammonium sulfate crystal producing apparatus



March 2, 1954 J. VAN ACKEREN AMMONIUM SULFATE CRYSTAL PRODUCING APPARATUS Filed Sept. 29, 1948 2 Sheets-Sheet l flm R m w W.

JosE P VAN ACKEEEN. 196.12%)

1 a 7'7'0P/VE March 1954 J. VAN ACKEREN 2,671,0

AMMONIUM SULFATE CRYSTAL PRODUCING APPARATUS Filed Sept. 29, 1948 2 Sheets-Sheet 2 IN VEN TOR. JOSEPH VAN ACKERE/V.

Patented Mar. 2, 1954 UN iTED STATES PATENT O'F'Flfi AMMONIUM SULFATE CRYSTAL PRO- DUOING PABAQ U tion of Delaware Application Septemb r 29, 5194 Ser al Na 1,724.

This invention relates to improved apharatus and to an improved method for treating gases, such as coke oven gas, to remove ammonia and imilar constituents therefrom.

It is customary in the art to recover-the am- .monia in coke oven gas by passing the gas through a saturator containing a weak sulfuric acid 591w tion through which the gassis bubbled with the result that the ammonia in the gaa'and thev sillfate radical in the acid'solution, combine tOLfer-m sulfate of ammonia which crystallizes out of the acid solution.

In order to obtain substantially complete removal of t mmoni from a a us mixture, i is necessary n t. nl or all o the s to com into C nt t W.ith theisulfuric a d bath, but to come in o contact with an a idic p t on of th bath capable of r actin with ammonia To secure adequate and effective contact between the as and the liqu d of the sulfuric-acid batlrit has b en customary t introduce the as into the liquid. Of the bath at a point a, substantial ,distance below theisurface ofthe liquid and-permit the gas to bubble upwardly through the liquid.

.An inherent disadvantage of thisarrangement is the relatively high pressure required toiforce the .gas :below ;the surfaceqof the liquid, and the rela- --.tively high cost of operating the compressors or tblowers for developing this pressure.

in the processes heretofore vemployed the gas leaving the sat-ureter carries :With itparticles of acid, and it has been customary to providaas a epa-ra-te piece of apparatus, an .acid separator for removing the acid from the gas leavingthe saturator and returning this acid to the saturater.

An object of this invention is to 'provide an'irnproved method and apparatus of the type described which eliminates the necessity for maintaining such pressure on the gaseous mixture as is required when it is introduced into-the acid bath in the saturator at a point belowthe level of the surface of the bath.

Another object of the invention is to provide an improved method and. apparatus of the type'described which eliminates thenecessity for-an acid separator as a separate piece of equipment.

A further object of theinvention is to provide arr-improved saturator which incorporates therein an acid separator.

Anotherobject ofthe invention is to provide an improved saturator in which there is no liquid seal to create back pressure to oppose the flow of the gaseous mixture through the saturator (i. re. the flow of gas is unobstructed th sensethat thereis no head ofiliquidiopposingzits flow) (ores-27s) A. ur her ohieetoftliein e ti is o p id anI m rQvsd s turator inw c e g us m ure isipassedthrqush a a id s ra n which the d rection o flow o the g u mixture 5 .continuousl altered'to thereby create turbulence and insur intimate an 'c mr te ad ix u o the ga andci acid as the a pass s ro s "th .atid spray.-

-A110ther objec of th invent onisto pro idea im o ed saturator o the typ described anrli which. a structural element, which is a part of the duct fo min a tortu o s path fo he ga enterins (the satu ator, isalso a part .of. the cyclon sep at r o removing acid rom t gas leavin lath .s ura or- A further object of the invention istpprovide an imp ove saturator o he type i e nb wh h s arrans qrs thatalarse olume iqu ay .be irculated wit a minimum ex ense .20 for pump n nother object o t e in entionis to ovide a "imp o ed sat ration-of he-tyne d s ibed w i is a ran ed so th t the vert cal di tance thr ug which liquid of the acid bath must be elevated is kept a the min mum to the eby rsdro the 'ex enseioipumping t elli ui .A -.further o jec f the inventio is to p ovide -an mp ed csaturatc o the typ des r be 'r hich. inco po es m a s or insur n e icien n substantial y complete emo al o th p rid ne and r lated tcsnstituent from 1 the gas passing through th saturator.

Another obi stioft e invention sto ro 'i an improved-retu ne o the hype bed which e he pro ucti n of ammon ofs ntrollable size.- Aziurther ob ec o the invent on is, to p o id asatur to incor o at n im r e for s in that me e i y i ra e threushon i cr stale Q s nbJ- cts of the i ven i n ani aiures novelty will e apparent .irom the following-des i tion -.tai n i c n ect on wi th accompanying .,d aw.inss which:

Fi 1 s a side elevation o my improverlsatugator, with a part broken away $9 Show the ine io construction;

Fig, 2 is a'top ,or plan View of the saturator 50-shown in "Fig.1;

l ig. 3 is a sectiona'l view :of the saturator and its associated apparatus taken on the line III-III =0fFig.-*2;

Fig. l-is a sectional view taken on the line :65 in: his. 1;

ing the lower portion of the saturator and the associated piping, with the supporting skirt omitted; and

Fig. 8 is a fragmentary enlarged sectional view showing a modification which I may employ.

In Figs. 6 and 7 of the drawings, in order to more clearly illustrate the arrangement of the apparatus, some of the pipe connections to the saturator are shown in somewhat different rotative positions than they are shown in the other figures of the drawings.

Referring to the drawings, it willbe seen that the saturator is generally cylindrical in form, and has a lower, or crystallizing bath-containing portion A, a central or absorbing portion 13, and an upper or acid-separator hood portion 0.

The saturator is preferably constructed of sheet stainless steel of a type which is resistant to the action or acid of the concentrations customarily employed. The various individual sections are welded together with suitable stainless steel welding rod to provide a gas and liquid tight structure, and the welded areas are thereafter ground and polished to present smooth surfaces which ofier little opportunity for the adherence of crystals. Hence, the tendency for salt incrustations to develop in the saturator is held to the minimum.

The lower or bath-containing portion A of the saturator is a substantially cylindrical sheet metal bowl H) which is closed at the bottom by a curved head. The upper edge of this bowl flares radially outwardly, as indicated at H, and is secured to the lower face of the bottom wall of the central or absorber portion B of the saturator.

The central or absorber portion B of the saturator is a vessel having a cylindrical outer wall 12 which is of somewhat larger diameter than the lower portion A of the saturator. The outer wall [2 is secured to a conical, dished head M, the surface of which slopes downwardly to a central slurry circulating pipe I of relatively large diameter.

A plurality of angular braces, orreinforcing members l6, are secured to the outer surface of the pipe I5 and to the bottom surface of the head M of the absorber portion B to accurately and rigidly secure the pipe I5 to the head 14.

A plurality of holes I! in the head I4 near the point of attachment of the bowl In with the head 14 prevent entrapment of gas in the upper part of the crystallizing portion of the saturator. The holes H are of such size, and their flow capacity is so limited, that the preferred hereinafter-described circulation of acid solution throughout the saturator is not materially affected by flow of solution through these holes.

The pipe I5 is of such length, as is clearly shown in Figs. 1 and 3, as to extend to a point a short distance above the bottom of the lower and a curved deflector I9 is secured in each of these openings.

As hereinafter explained, a portion of the liquid flowing downwardly in the pipe i5 is diverted by the deflectors 19 through the openings [8 and thence upwardly in the crystallizer bowl.

The upper or acid-separator hood portion C includes a substantially cylindrical member 20 of somewhat smaller diameter than the wall I2 of the absorber portion B of the saturator. The member 20 is located centrally or coaxially of the wall l2 of the absorber portion, and, as is best shown in Fig. 3, the member 28 extends downwardly within the wall I2 to a point a short distance above the head or lower wall 14 of the absorber portion B. The lower end of the cylindrical member 26 is open, while a plurality of inwardly extending ribs 2| are secured on the inner face of the member 28 and prevent swirling or circular motion of the liquid in the saturator.

The upper end of the cylindrical member 20 'is closed by a head 22 through which extends a centrally located pipe 23, Fig. 3, of relatively large diameter. The pipe 23 extends downwardly from the head 22 a substantial distance, the lower end of the pipe 23 being open and being located some distance above the lower edge of the member 20. The upper end of the pipe 23 is surrounded by a flange 24 and serves as the outlet for gas leaving the saturator.

As explained above, the cylindrical hood member 29 and the cylindrical wall l2 are substantially concentric, and the member 20 extends within the wall 12. Hence, an arcuate or curved channel passageway or absorption chamber 25 is formed between the members 12 and 20, the outer wall of the chamber being formed by the wall [2, and the inner wall of the chamber being formed by the member 28.

As can be seen from the above description and from the drawings, passageway or chamber 25 defines a relatively narrow elongated absorption chamber or zone Whose use and operation are described more fully below.

The wall I2, together with the lower wall or head l4, form a vessel which is adapted to hold a body of solution, and the cylindrical member 20, together with the head 22, form an inverted vessel which helps to close the top of the absorber portion B as well as to function as an acid separator. The member 29 and the associated elements may also be considered as a conduit through which gas leaving the saturator passes.

A relatively large opening 26, Fig. 1, is provided in the wall [2 and serves as an inlet for the flow of gas into the channel absorption chamber 25 and thus into the saturator.

A portion of the chamber 25 diametrically opposite from the inlet opening 25 communicates with a vertically extending passage 28, Figs. 3 and 4, the inner wall of which is formed by the cylindrical member 28 and the outer wall of which is formed by an upward extension of the wall 12. Hence, the radial extent of the passage 28 is the same as the chamber 25, while the circumferential extent of the passage 23 is such that the cross-sectional area of this passage is approximately the same as that of the inlet opening 26.

The upper end of the vertical passage 23 communicates with a horizontal passage 29, Figs. 1

and 4, which extends a portion of the distance around the cylindrical member 2:]. As is best shown in Fig. 4, the cylindrical member as has an opening therein into which the passage 2?: connects, the outer wall of the passage 29' being Zturuedadjaoent the-vertical passagemeand gradiually merging into :a :substantially straight aperition whichzisztangent :to the zcylindricalrmember 220. The :portion -.:of "the rcylindrioal .unemher 32.0 on :the. side .n'f the opening "in athis tmember tadjacent ithe Mertical-spassage l28 curred .inward sslightlygas indicated :at

. "Theil'ower awa'llnf ithehorizontal passage 52.9 is :formed by .n ccurvedtplate 32, .1, which also :iorms one side wall of 'the vertical massage 28. The upper wall of the .horizontal :passage 329 .is .iformed by aplate .13 3, .oneiend of which curves 11pwardly :and is :ioinedtoa plate 34., whichvcloses the upper end of the -:ve1 'tica1 passage :28. The

other side :wall :of the werti'cal passage 28 .is

stormed hynznlate -35. Eig. A.

The upper'faceeof themhamber :25 .is zfilOSQd hy .amarcuate plate 3.1, Fig. .3, which :extends circum- -ierm'tially .around the saturator from the -;plate 23.5 at -.one.:side of :the vertical passage ."28 to the 'gplater32 at;-the other side-of thegpassage :2 8.. .The iinner edge :of :the plate .37 :is secured .to the 10341221 .face :Of the cylindrical member -20, while .the

-';outer :edge .of :the plate :31 secured to the to :of the :wall 12.

.A curved zplate -40, Figs. .1 and 2, :is secured on .4316 dipper face of the 'plate 31 near its outer edge and extends around the saturator jrom the ,plate .32 ron oneside -:of :the vertical passage 28 to "the plate .35 .on the other side :of the vertical g-pas- .memberemrcooperate to form an arcuate .duct .42,

Figs. .3 and 4, extending around the saturator except where the vertical passage .28 :is located. .An inlet to theduct 42 .isgprovidedeatlapoint substantially :opposite the vertical passage 28 .so zthat theinearlysemieciroularportionsof the duct :ion opposite .sides of the .inlet 43 .aresiibstantially equal length.

:A plurality .of downwardly directednozzlesfli, Figs. l-anddi, are secured in the .plateBl .andare llocated substantially intermediate the walls 1.2 .and 20 so-thatthespray from the'nozzlesfills the channelabsorption chamber-25. The nozzles 4.5 may be secured .in the plate-31 in .any desired manner, while .the plate 4| .has openings therein directly above the nozzles :to permitreadyaccess to the-nozzles. The openings. in the plate All -3.-I.61C10Sfid by suitablecover plates lfijigs. l, 2, 3 and .4. The duct 42 .forms a manifold .oreheader .for supplying acid solution to the nozzles 4'5.

Thenozzles 45 .extend downwardly .from the ,plate 131 .a substantial distance, and means providedto preventcirculation ofgasin the portion of the chamber '25 above the tips of the nozzles. .As shown .inEig. .3, plates 4.1 and 48 extend downwardly :from the plate I31 .on opposite sides of the nozzles .45. The ,plates 45.1 and :43

.areilocated relativelynear :the nozzles 45 .so there islittle space for Jiow .of gas .between .these plates :and the: nozzles.

.Theplates 4.! andl48are curved, asyiewedirom the top of the saturator, and .extend throughout the chamber 25. A conical plate 50 extends. from the plate '4? to member 12, while .a similar plate extends from the plate .48 to .the cylindrical member "20. The plates "41, '48, "El! and 5], therefore, enclose thearea abovethe'tips ofthenozzles The plate 4! extends .315 amd substantial-1y zexclu'de gas :irom "flowing Pin ':the region above the spray ifrom tithe nozzles.

This prevents gas .from passing :through the .zsaturator without being .exposeditospray :of solution from the :nozzles, land :it inhibits accumulaztion :of salt onuthezsurfaces above ithenozzles.

inf-Fig. -;8 :of i-the drawings atheresis shown :a dilierent arrangement for preventing 'ifiow 50f gas the .iareaabove ithetips .o'f z-themozzles. :I-nithis modification a plurality :of rradially extending plateszflare: provided. "These plates :extend Jfrom :theaouter face ofttheicylindricalimemberfl0 toithe iinnersface .of :the wall 1-2., and the .upper iedg-e o'f each-pfthese-plates is .securedxto the slowereifa'ce of the plate 37. The lower side of eachzof XQIRCBS :53 .has therein .a vcentrally located atri- .-ang-ularzno.tc'h which iSxOf such :size andi lecation rthat :thespray .from adjacent nozzles 4'55 rii'lls :the :area =.of :the vnotch. The :plates 153 effectively prevent *flowaof-gas the area above thespray from :the nozzles 45., andinsure that all of the .gas :fiowing through the chamber comes into contact with spray from the nozzles :45.

.Two nozzles 52, Figs. 2, 3 and :6, are mounted the top plate iii-lat the upper end of the .passage 228.. The nozzlesaS'Z spray liquid :into-thegas as it passes'rupwardly in thepassage 2t. .Asihereinafteraexplaineitheliquid for the nozzles 52 is preferably supplied from adifierent source than the horrid supplied to the nozzles d5.

This .sa-tu-rator includes a liquid level control means .,-for maintaining .the liquid .in the "saturator at a selected level. As illustrated this .jliquid level control means icomprises an overflow pipe M rie. .3, whichprojects-through .the wall 4:4 :and extends upwardly to .a .point .a substantial .dis- -tance, such :aslO inches, above the bottom of the cylindrical memberifl. The oyerflowpipe-filde- .termines the level of :the liquid inthesaturator .and this is fixed at .a selected levelthigheneugh above the bottom of themember -28 to prevent gas from the chamber 2.5 from ,fiowing under the bottom of the cylindrical -memb.er and thence to the outlet pipe 2.3 without passing through the vertical passage 23., and through the separator portion .of the saturator. The overflow pipe .54 communicates with the .usual tai -skimmer tankl'l'.

head :55, .Fig. .is secured .to the inner face of the wall vI2 and covers the openinginto the gpipe .54 so that spray from the nozzles am 52 *will not flow directly into .the overflow pipe 54. The'upper edge of the hood .55 sissecu-red :to the wall -12 while the lower edge of the hood iextendszin wardly beyond the;pip1e 54,, -and a short distance, such as 4 inches, .above the .pi e :54. i-Iihe hood extends at -a relatively steeprangle iso liquid willflow off itrrapidlyand thus; prevent the deposit =of crystals on this member.

.A pipe ifi -Figsus iand 4,.communicates withithe interior of .the saturator at a point beneath the hood 55. The pipe 5651112153 beemployedtospray .hot water on the overfiowpipe 54 and thus z'prewent-clogging of :this pipeiby tar which is carried linto the.saturatorhy the gas.

'Theasaturatorhas associated therewith apuinp for circulating liquor in the :lower or bath contaming portion 10f 'ithe :saturator and .for -supplyi'ing liquor'to *the nozzles 45. Referring to Figs. 6 and 7, it will beseen that a motor driven pump Pl is provided and that the inlet of tliispump "communicates with the lower or bath-containing portion A "of the'saturatorby apipe'tl. Thegpipe 6.! pensint'o the'lowergportion Act the saturator through a suction'head 6'2, which is a substanpipe '83 to the nozzles 52.

tially rectangular bowl-shaped member, which is open only at the top. The side walls of the member 82 flare outwardly, as shown in Fig. 6, so that the opening into the suction head is of relatively large area with the result that the velocity of the liquid flowing into the suction head is correspondingly low. The upper edge of the side walls of the suction head 62 is in substantially the same horizontal plane throughout the periphery of this member so that the flow of liquid into the suction head is at a substantially uniform rate at all points. As is obvious in Figs. 1 and 3 of the drawings, the suction head 62 is located near the top of the lower portion A of the saturator.

The pump PI supplies liquid through a pipe 63 to the duct 42, Fig. 3, and thus to the nozzles 45. The duct 42, therefore, serves as a manifold or header for supplying liquid to the nozzles 45. A branch pipe 64, Figs. 6 and 7, governed by a valve 65, leads from the pipe 63 to a connection 86 which opens into the saturator at a point below the level of the liquid in the saturator. The bypass pipe 64 and the valve 65 enable the circulation of liquid in the saturator to be increased by a variable amount in excess of that provided by the flow of liquid through the nozzles 45.

A pipe 61, Fig. 7, connects to the inlet pipe 8! at a point between the pump PI and the saturator and leads to the interior of the saturator at a point above the level of the liquid in the saturator. The pipe 61 is a vent and provides means for the escape of gases from the inlet pipe 5!.

Suction heads 10, Figs. 1 and 3, of conventional construction, extend into the lower portion'of the bowl l and provide means for withdrawing ammonium sulfate crystals from the saturator and for supplying the sulfate to a centrifugal dryer, not shown. Liquid removed from the crystals in the dryer is returned to the saturator l through the pipe connection 1 I.

A relatively large opening 72, Figs. 1 and 3, is provided in the bowl Hi and is closed by a cover 13. This opening enables workmen to secure access to the interior of the lower portion of the saturator during its construction, or for maintenance purposes, after it has been in use.

A skirt 88, Figs. 1 and 3, surrounds the saturator and is secured to the exterior of the member l2. The skirt 80 extends downwardly and rests upon suitable supporting means, such as the reinforced concrete abutments 81, to provide a support for the saturator.

Liquid from the tar tank T overflows into a storage tank ST, from which it is pumped by a suitable pump -P2 to a pipe 83, Figs. 1, 2 and 3, and thus to the nozzles 52. Make-up acid from an acid storage tank AST is also supplied to the storage tank ST, and thus is supplied through The amount of makeup acid supplied from the acid storage tank AST to the tank ST is regulated so that the liquid discharged from the nozzles 52 has an acid content about twice as high as the liquid in the saturator bath, that is, about 11% acid in the spray from the nozzles 52, as compared to about 5 acid in the saturator bath.

Make-up acid, in addition to that supplied through the nozzles 52, may be supplied to the saturator in any desired manner.

Under normal operating conditions the bath level in the saturator is maintained approximately constant by the overflow pipe 54, whiie liquid is withdrawn from the upper part of the bowl [8 by the pump Pl through the suction head 62,

and is supplied to the headeror manifold 42 from which it flows through the nozzles 45 and is sprayed throughout the absorption chamber 25 and falls to the surface of the bath at the bottom of this chamber. In addition, liquid supplied by pump Pl through the by-pass pipe 64 is added to the bath at the bottom of chamber 25. Similarly, the liquid discharged from the nozzles 52 at the upper end of the vertical passage 28 is sprayed throughout the passage 28 and falls to the surface of the liquid in the saturator.

Likewise, liquid which collects on the interior of the Wall 20 of the acid-separator portion C of the saturator flows down this wall and adds to the liquor in the saturator bath. It will be seen that the arrangement for the return of liquid from the acid-separator to the saturator bath is such that it is unnecessary for this liquid to flow through small pipes which may become clogged by salt deposits. The incorporation of the acid separator in the saturator, therefore, eliminates a troublesome operating difficulty which exists when the acid separator is an independent unit.

The liquid in the portion of the saturator above the header ordivision wall l4 flows downwardly through the pipe 15 to the lower or bath-containing portion of the saturator to replace the liquid removed by the pump P l.

Coke oven, or other gas to be processed, is supplied to the saturator through the inlet opening 25, Fig. 1 and 3, to the chamber 25 and the vertical passage 28. The vertical passage 28 is diametrically opposite the inlet opening 25 while the channel 25 which is located radially outwardly of the cylinder member 20 provides two paths in multiple through which gas may flow from the inlet opening 26 to the vertical passage 28. As viewed in Figures 2 and 3 of the drawings one of the channels extends from the inlet opening 25 in a clockwise direction around the member 2 2, while the other channel extends from the inlet opening 25 in a counterclockwise direction around the member 29. Both of these channels communicate with the lower end of the passage 28.

As the gas passes through the chamber 25, it must pass through spray from the nozzles 45 which, as can be seen from the drawing are uniformly distributed over the entire length of absorption zones 25. This spray is extremely dense and completely fills the chamber 25. The rate of flow of gas through the chamber 25 is relatively high so that the gas is extremely turbulent. Furthermore, because of the curvature of the two portions of the chamber 25 through which the gas flows, the gas in flowing through these portions is constantly changing direction and there is no laminar flow of gas or stratification of the gas. Due to the extended gas-liquid interface existing in the mixture of spray and gas, the absorption of ammonia proceeds rapidly to completion and by the time the gas reaches the vertical passage 28, it is substantially free of ammonia. The turbulent flow of gas through the channels 25 is also very efiective in bringing the gas into contact with the acid absorbing liquid which forms the bottom walls of the channels.

As just explained, the gas supplied through the inlet passage 26 divides into two streams flowing horizontally in curvilinear paths, one of which flows in one direction through a substantially semi-circular portion of chamber 25 while the other gas stream flows through the other portion of the chamber 25. Hence, there are two arcuate paths in multiple between the inlet opening 26 and the vertical passage 28, and each of these pathsv is; required to: handle. onlyrone-halr: of; the gas... Hence; eachzpath can.bezotsmaller crosss sectional area than. would: be necessary if." each path was required" to handlethe entire volumeiof. gas; Astaresu1t,'.the: chamber 25: may bemade of substantially smaller size and oi'lesser'vertical': extent than would. otherwise: be" required;v Thereduced' verticali extent." of: the. chamber 25; reduces-thevertical distance: through which. liquid must be pumped to the nozzles 45, so .th'e'ipumping; cost is: reduced. to: thezminimum..

The gas streams flowing through the two. porl: tlons of the chamber 25 in. multiple: meet. at the-base of the vertical passages 28. andfiowupwardl'y' through this passage .incountercurrent to the liquid sprayed? from the nozzles at the top of. this passage.

As" previously explained, theliquid sprayed: from. the nozzles 52 a substantially higher: acid content, than that supplied. from the nozzles 45 This liquid of high acid content: has a-greater afiinity' for pyridine and its congeners than the: liquid of low acid content, and, therefore, removes the gas passing through the vertical passage 25, any of these constituents not removed by passage of. the gas through the chamber'25;

The: liquid from the nozzles 52,, together with the pyridine and other constituents; absorbed thereby, adds to the bath in the saturator and increases the'pyridine concentration of this bath. The pyridine maybe removed from. the bath byany suitable means well known. in the art so. as to maintain thepyridine-concentration of. the saturator bath at. a satisfactorily low level to. thereby make possible substantially complete re-- covery of the pyridine;

When the gas reaches the upper part of the vertical passage 28, thegas flows: through the horizontal passage 29: and. is discharged tangen ti-a-lly into the chamber within the memb'er'zfl and outside the pipe 23.

The gas discharged from the passage 29 is flowing at high velocity and when discharged tangentially into the chamber within the member-:20,- the gas flows around and around within the hood member 20. at high speed so that entrained liquid carried by the gas is. thrown radially out-- wardly against the member 20' and. then. drains= down. into the saturator bath;v The. entrained liquid. is thereby removed fromthegas. within the-member 20 graduallyflows downwards lyand loses velocity, andthen reverses its direction and flows upwardly into the pipe. 23 and. thence from the saturator, but by the-:timethe gas reaches the pipe 23', substantially all of. the free liquid is removed therefrom.

As pointed. out above, the baffles 2 ii on. the inside of the member 2t prevent the rapidly ro.- tating: gas. within the member 2.0 from causing the liquid within the member 20. to swirl or rotate.

As explained above, the liquid sprayed from the nozzles 45 and 52 absorbs ammonia and other constituents from the gas, while this liquid is: added'to the portion of the saturator bath above the header 14, thereby increasing the concentration of ammonium sulfate in this portion of the bath. In addition, as explained above, due to the action of the pump Pl inv removing'liquid from the lower or bath-containing portion A of the saturator, liquid continuously flows from the portion of the bath abovethe header M through the pipe :5, from which the liquor is discharged near: the bottom of. the bowl [0. Theeliquid discharged from the pipe l5 then flows upwardly try-- Thegas wardssthe'suction head 62 where theliquid: flows to; the pump BI and is recirculated. There. is, therefore; aconstant circulation of: liquid insthe saturator over the; path which includes. the suction head 62; the'pump Pl, the spray nozzles 45, and the. by-pass pipe 54, thence downwardly through. the pipe l5; and upwardly through the bath-containing portion of the saturator to they suction: head 62-. There is, therefore, a continuous upward movement .of the liquid in the bowl I0, that is: in the bath-containing portion A of the saturator.

The various parts of the lower or bath-cone tainihgr portion A. of. the saturator." are so arranged. that "the rate of flow of liquid upwardly in: thebowl id is substantially uniform. throughout the entire area off the bowl It. The liquid discharged from the; lower end. of the pipe I5: impingeson the bottom of the. bowl and flows radially outwardly and thence upwardly in the region adjacent the wall of the. bowl It, that isin the radially outer portion of the bowl to. Atthe-same time some of the liquid flowing down-.. Wardly through the pipe I5 is diverted by the deflectors l9) through the openings I8 and thence upwardly in the region adjacent the pipe [5, that is in the radially inner portion of the bowl Ill. The liquid diverted through the openings l8. by the deflectors l9 not: only createsan upward flow of'liquid in the central portion of the bowl H), but. also prevents liquid discharged. from the. lower end of the pipe l5, and flowing'upwardly in the outer portion of'the bowl. Hi, from flowing downwardly in the region. adjacent the pipe [5.- Accordingly, there is an upward movement of liquid in all portions of; the bowl. l9, and the rate of movement of liquid upwardly is substantially uniform throughout: the area of the bowl Hi atthat: level.

The solution which is sprayed through the nozzles and is thus brought into contact with the ammonia-containing gas, is in a substantial- 1y saturated condition when it leaves the nozzles. This solution is brought to a supersaturatedcondi-tion' by absorption of ammonia from the gas.

Accordingly, the liquid discharged from the pipe I5 into the lower portion of. the bowl I0 is a supersaturated solution. The supersaturation of this liquid, is released. (1. e. the liquid is de supersaturated) by contact with, the crystals which arein suspension in the body of liquid in thelower or bath-containing portion of the: saturator, whereupon the solution is returned to the nozzles 45 and is again brought into contact:

with'the gas so that the cycle is: repeated.

The ammonium sulfate deposited on the crystals in the lower portion of the saturator causes: these crystalsto grow in size so they settle to' the lower portion of the bowl where they are attracted by the suction heads 10.

As the rate of. flow of liquid upwardly in the bowl Ill is substantially uniform throughout the entire area of the bowl 10', the crystals settling to the lower part of the bowl ill are of substantially uniform size throughout the area of the circulated. These are discharged from the pipe 15' into the lower portion of the bowl !0. Some of these minute-crystals will be attracted to the ll suction heads 12 and will be included in the slurry withdrawn from the saturator. However, the amount of these crystals is relatively small and is not objectionable.

The rate of supply of ammonia-containing gas to the saturator, and the rate of circulation of the liquid through the saturator, are correlated in such manner that the concentration of ammonium salts in the liquid in the saturator does not materially exceed the concentration at which new crystals are formed in the absence of seed crystals, and preferably does not exceed that concentration at which new crystals form in the presence of seed crystals. This condition is known to those skilled in the art as being in the metastable but not in the labile region of supersaturation. This condition limits or represses the formation of new crystals and aids in the formation of relatively large crystals.

The bulk of the liquid circulated through the saturator fiows through the nozzles 45 which are of fixed size. The by-pass pipe 64 and the valve 65 provide means for varying the rate of circulation of solution in the saturator so that the size of the crystals which are produced under varying operating conditions can be accurately controlled.

It will be seen that this saturator incorporates an acid separator for removing free liquid from the gas before the gas leaves the separator. In addition, it will be seen that the arrangement of the saturator is such that the structural elements employed in the acid-separator portion of the saturator also serve as part of other portions of the saturator.

As explained above, the cylindrical member 20, which forms the outer wall of the upper or acidseparator portion of the saturator cooperates with the wall l2 of the central or absorber portion B of the saturator to form the arcuate duct or passage 25 through which the gas passes while being subjected to the spray from the nozzles 45.

The cylindrical member 20 also forms a part of the vertical passage 28, and, in addition, forms a part of the manifold or header 42 for supplying liquid to the nozzles 45. Furthermore, the separator portion 0 of the saturator, and comprising the member 20 and the head 22, is in effect an inverted vessel and cooperates with the parts associated with the duct 42 and the vertical passage 28 to enclose the upper portion of the saturator, thereby making it unnecessary to provide separate means for enclosing the top of the saturator.

It will be seen also that the lower end of the cylindrical member 28 is open, but that it extends below the level of the liquid in the saturator so that the liquid seals this end of the member 20. This not only makes it unnecessary to provide a bottom or head for the acid-separator portion C of the saturator, but it also provides a structure with a minimum of places for salt crystals to accumulate, while any salt which does build up will be dissolved during the kill due to the contact of the member 20 with the liquid of the bath. The arrangement of the saturator is such, therefore, that it forms a compact unit which requires a minimum of expensive material for its construction.

Subject matter disclosed but not claimed herein, for instance features which relate broadly to apparatus or method, are the subject matter of one or more of the following co-pending applications, Serial No. 338,367, filed February 241,

12 1953. Serial No. 338,368 filed February 24, 1953, and Serial No. 323,615 field December 2, 1952.

Although I have herein illustrated and described only one form of improved method and apparatus for removing ammonia and other constituents from coke oven gas, it is to be understood that various changes in the method or apparatus may be made without departing from the spirit and scope of my invention as set forth in the appended claims.

Having thus described my invention, what I claim is:

1. A closed vessel for separating a component of a gaseous mixture by adsorption in a liquid which forms crystals as a result of such adsorption comprising; a chamber adapted to contain a body of liquid in the lower portion and comprising a downwardly sloping bottom, means cooperating with said chamber to define arcuate elongatedhorizontal gas impermeable passageways for gas which are bounded at the bottom by said body of liquid, means for introducing and removing gas from said passageways, means for spraying liquid downwardly over the entire lengths of said passageways, a crystallizing chamber disposed below and adjacent the liquid-containing chamber, a conduit extending downwardly from the lowermost portion of the bottom of the liquid-containing chamber into the crystallizing chamber, the bottom of said conduit being in spaced relation to the bottom of the crystallizing chamber, means for deflecting liquid flowing downwardly in said conduit upwardly adjacent the outer periphery of said conduit,

' means for withdrawing liquid from the top portion of said crystallizing chamber and pumping it to said means for spraying liquid, and means for withdrawing crystals from the bottom portion of said crystallizing chamber.

2. A closed vessel for separating a component of a gaseous mixture by adsorption in a liquid comprising; an upper chamber comprising a first vertical cylindrical member, said member being open at the bottom, a lower chamber having a downwardly sloping bottom and comprising a second vertical cylindrical member of greater diameter than said first cylindrical member positioned in spaced overlapping relation thereto so as to define an annulus therewith, an arcuate closure member for the top of said annulus, an overflow conduit in said lower chamber with its top spaced above the bottom of said first cylindrical member, a gas inlet to said annulus, a gas outlet from said annulus positioned at the top of said annulus diametrically opposite to said gas inlet and communicating with the interior of said first vertical cylindrical member, a plurality of downwardly directed liquid spray noz-j zles positioned in the upper portion of said annulus, means for removing liquid from the bottom of said lower chamber, and means for supplying liquid to said spray nozzles.

3. A closed vessel for separating a component of a gaseous mixture by adsorption in a liquid comprising; an upper chamber comprising a first vertical cylindrical member, said member being open at the bottom, a lower chamber having a downwardly sloping bottom and comprising a second vertical cylindrical member of greater diameter than said first cylindrical member positioned in spaced overlapping relation thereto so as to define an annulus therewith, an arcuate closure member for the top of said annulus, an overflow conduit in said lower chamber with its top spaced above the bottom of said first cylindrical member, a gas inlet to said anulus, a gas passageway from the top of said annulus to the interior of said first cylindrical member positioned diametrically opposite to said gas inlet, a plurality of downwardly directed liquid spray nozzles positioned in the upper portion of said annulus, means for removing entrained liquid from the gaseous mixture positioned in the upper portion of said upper chamber, means for removing liquid from the bottom of said lower chamber, and means for supplying liquid to said spray nozzles.

4. A closed vessel for separating a component of a gaseous mixture by adsorption in a liquid which forms crystals as a result of such adsorption comprising; an upper chamber comprising a first vertical cylindrical member, said member being open at the bottom, a lower liquid-containing chamber having a downwardly sloping bottom and comprising a vertical cylindrical member of greater diameter than said first cylindrical member positioned in spaced overlapping relation thereto so as to define an annulus therewith, an arcuate closure member for the top of said annulus, an overflow conduit in said lower chamber with its top spaced above the bottom of said first cylindrical member, a gas inlet to said annulus, a gas outlet from said annulus positioned at the top of said annulus diametrically opposite to said gas inlet and communicating with the interior of said first vertical cylindrical member, a plurality of downwardly directed liquid spray nozzles positioned in the upper portion of said annulus, a crystallizing chamber disposed below and adjacent the liquid-containing chamber, a conduit extending downwardly from the lowermost portion of the bottom of said liquid-containing chamber into the crystallizing chamber, the bottom of said conduit being in spaced relation to the bottom of the crystallizing chamber, means for withdrawing liquid from the top portion of said crystallizing chamber and pumping it to the spray nozzles, and means for withdrawing crystals from the bottom portion of said crystallizing chamber.

5. A closed vessel for separating a component of a gaseous mixture by adsorption in a liquid comprising; an upper chamber comprising a, first vertical cylindrical member, said member being open at the bottom, a lower chamber having a downwardly sloping bottom and comprising a second vertical cylindrical member of greater diameter than said first cylindrical member positioned in spaced overlapping relation thereto so as to define an annulus therewith, a flat arcuate closure plate extending around the top of said annulus, an overflow conduit in said lower chamber with its top spaced above the bottom of said first cylindrical member, a gas inlet to said annulus, a gas outlet from said annulus positioned at the top of said annulus diametrically opposite to said gas inlet and communicating with the interior of said first cylindrical member, an arcuate liquid manifold disposed above and employing as its bottom boundary said flat arcuate closure plate, a plurality of downwardly directed liquid spray nozzles in communication with said liquid manifold and positioned in the upper portion of said annulus, means for removing liquid from the bottom of said lower chamber, and means for supplying liquid to said liquid manifold.

6. A closed vessel for separating a component of a gaseous mixture by adsorption in a liquid comprising; an upper chamber comprising a first vertical cylindrical member, said member being open at the bottom, a lower chamber having a downwardly sloping bottom and comprising a second vertical cylindrical member of greater diameter than said first cylindrical member positioned in spaced overlapping relation thereto so as to define an annulus therewith, a closure member for the top of said annulus, an overflow conduit in said lower chamber with its top spaced above the bottom of said first cylindrical member, a, third vertical open ended cylindrical member of lesser diameter than said first cylindrical member positioned in the upper chamber with its bottom at a level above the top of said overflow conduit, a gas inlet to said annulus, a gas passageway from said annulus positioned at the top of said annulus diametrically opposite to said gas inlet and shaped to deliver gas tangentially to the interior of said first cylindrical member, a plurality of downwardly directed spray nozzles positioned in the upper portion of said annulus, means for removing liquid from the bottom of said lower chamber, and means for supplying liquid to said spray nozzles.

JOSEPH VAN ACKEREN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 353,517 -'Osborne May 14, 1907 1,264,263 Brassert Apr. 30, 1918 1,895,652 Fisher Jan. 31, 1932 1,936,308 Mueller Nov. 21, 1933 2,375,922 Jeremiassen May 15, 1945 2,424,205 Otto July 15, 1947 2,424,206 Otto July 15, 1947 2,439,547 Otto Apr. 13, 1948 2,482,683 Tiddy Sept. 20, 1949 

1. A CLOSED VESSEL FOR SEPARATING A COMPONENT OF A GASEOUS MIXTURE BY ADSORPTION IN A LIQUID WHICH FORMS CRYSTALS AS A RESULT OF SUCH ADSORPTION COMPRISING; A CHAMBER ADAPTED TO CONTAIN A BODY OF LIQUID IN THE LOWER PORTION AND COMPRISING A DOWNWARDLY SLOPING BOTTOM, MEANS COOPERATING WITH SAID CHAMBER TO DEFINE ARCUATE ELONGATED HORIZONTAL GAS IMPERMEABLE PASSAGEWAYS FOR GAS WHICH ARE BOUNDED AT THE BOTTOM BY SAID BODY OF LIQUID, MEANS FOR INTRODUCING AND REMOVING GAS FROM SAID PASSAGEWAYS, MEANS FOR SPRAYING LIQUID DOWNWARDLY OVER THE ENTIRE LENGTHS OF SAID PASSAGEWAYS, A CRYSTALLIZING CHAMBER DISPOSED BELOW AND ADJACENT THE LIQUID-CONTANING CHAMBER, A CONDUIT EXTENDING DOWNWARDLY FROM THE LOWERMOST PORTION OF THE BOTTOM OF THE LIQUID-CONTAINING CHAMBER INTO THE CRYSTALLIZING CHAMBER, THE BOTTOM OF SAID CONDUIT BEING IN SPACED RELATION TO THE BOTTOM OF THE 